/* Copyright (c) 2010, Carl Burch. License information is located in the
 * com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

package com.cburch.logisim.std.arith;

import java.awt.Color;
import java.awt.Graphics;
import java.util.Arrays;

import com.cburch.logisim.data.Attribute;
import com.cburch.logisim.data.AttributeOption;
import com.cburch.logisim.data.Attributes;
import com.cburch.logisim.data.BitWidth;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Location;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.Instance;
import com.cburch.logisim.instance.InstanceFactory;
import com.cburch.logisim.instance.InstancePainter;
import com.cburch.logisim.instance.InstanceState;
import com.cburch.logisim.instance.Port;
import com.cburch.logisim.instance.StdAttr;
import com.cburch.logisim.tools.key.BitWidthConfigurator;
import static com.cburch.logisim.util.LocaleString.*;

public class Shifter extends InstanceFactory {
    static final AttributeOption SHIFT_LOGICAL_LEFT
        = new AttributeOption("ll", getFromLocale("shiftLogicalLeft"));
    static final AttributeOption SHIFT_LOGICAL_RIGHT
        = new AttributeOption("lr", getFromLocale("shiftLogicalRight"));
    static final AttributeOption SHIFT_ARITHMETIC_RIGHT
        = new AttributeOption("ar", getFromLocale("shiftArithmeticRight"));
    static final AttributeOption SHIFT_ROLL_LEFT
        = new AttributeOption("rl", getFromLocale("shiftRollLeft"));
    static final AttributeOption SHIFT_ROLL_RIGHT
        = new AttributeOption("rr", getFromLocale("shiftRollRight"));
    static final Attribute<AttributeOption> ATTR_SHIFT
        = Attributes.forOption("shift", getFromLocale("shifterShiftAttr"),
                new AttributeOption[] { SHIFT_LOGICAL_LEFT, SHIFT_LOGICAL_RIGHT,
                    SHIFT_ARITHMETIC_RIGHT, SHIFT_ROLL_LEFT, SHIFT_ROLL_RIGHT });

    private static final int IN0   = 0;
    private static final int IN1   = 1;
    private static final int OUT   = 2;

    public Shifter() {
        super("Shifter", getFromLocale("shifterComponent"));
        setAttributes(new Attribute[] {
                StdAttr.WIDTH, ATTR_SHIFT
            }, new Object[] {
                BitWidth.create(8), SHIFT_LOGICAL_LEFT
            });
        setKeyConfigurator(new BitWidthConfigurator(StdAttr.WIDTH));
        setOffsetBounds(Bounds.create(-40, -20, 40, 40));
        setIconName("shifter.svg");
    }

    @Override
    protected void configureNewInstance(Instance instance) {
        configurePorts(instance);
        instance.addAttributeListener();
    }

    @Override
    protected void instanceAttributeChanged(Instance instance, Attribute<?> attr) {
        if (attr == StdAttr.WIDTH) {
            configurePorts(instance);
        }
    }

    private void configurePorts(Instance instance) {
        BitWidth dataWid = instance.getAttributeValue(StdAttr.WIDTH);
        int data = dataWid == null ? 32 : dataWid.getWidth();
        int shift = 1;
        while ((1 << shift) < data) shift++;

        Port[] ps = new Port[3];
        ps[IN0]   = new Port(-40, -10, Port.INPUT,  data);
        ps[IN1]   = new Port(-40,  10, Port.INPUT,  shift);
        ps[OUT]   = new Port(  0,   0, Port.OUTPUT, data);
        ps[IN0].setToolTip(getFromLocale("shifterInputTip"));
        ps[IN1].setToolTip(getFromLocale("shifterDistanceTip"));
        ps[OUT].setToolTip(getFromLocale("shifterOutputTip"));
        instance.setPorts(ps);
    }

    @Override
    public void propagate(InstanceState state) {
        // compute output
        BitWidth dataWidth = state.getAttributeValue(StdAttr.WIDTH);
        int bits = dataWidth == null ? 32 : dataWidth.getWidth();
        Value vx = state.getPort(IN0);
        Value vd = state.getPort(IN1);
        // y will by x shifted by d
        Value vy;
        if (vd.isFullyDefined() && vx.getWidth() == bits) {
            int d = vd.toIntValue();
            Object shift = state.getAttributeValue(ATTR_SHIFT);
            if (d == 0) {
                vy = vx;
            } else if (vx.isFullyDefined()) {
                int x = vx.toIntValue();
                int y;
                if (shift == SHIFT_LOGICAL_RIGHT) {
                    y = x >>> d;
                } else if (shift == SHIFT_ARITHMETIC_RIGHT) {
                    if (d >= bits) {
                        d = bits - 1;
                    }

                    y = x >> d | ((x << (32 - bits)) >> (32 - bits + d));
                } else if (shift == SHIFT_ROLL_RIGHT) {
                    if (d >= bits) {
                        d -= bits;
                    }

                    y = (x >>> d) | (x << (bits - d));
                } else if (shift == SHIFT_ROLL_LEFT) {
                    if (d >= bits) {
                        d -= bits;
                    }

                    y = (x << d) | (x >>> (bits - d));
                // SHIFT_LOGICAL_LEFT
                } else {
                    y = x << d;
                }
                vy = Value.createKnown(dataWidth, y);
            } else {
                Value[] x = vx.getAll();
                Value[] y = new Value[bits];
                if (shift == SHIFT_LOGICAL_RIGHT) {
                    if (d >= bits) {
                        d = bits;
                    }

                    System.arraycopy(x, d, y, 0, bits - d);
                    Arrays.fill(y, bits - d, bits, Value.FALSE);
                } else if (shift == SHIFT_ARITHMETIC_RIGHT) {
                    if (d >= bits) {
                        d = bits;
                    }

                    System.arraycopy(x, d, y, 0, x.length - d);
                    Arrays.fill(y, bits - d, y.length, x[bits - 1]);
                } else if (shift == SHIFT_ROLL_RIGHT) {
                    if (d >= bits) {
                        d -= bits;
                    }

                    System.arraycopy(x, d, y, 0, bits - d);
                    System.arraycopy(x, 0, y, bits - d, d);
                } else if (shift == SHIFT_ROLL_LEFT) {
                    if (d >= bits) {
                        d -= bits;
                    }

                    System.arraycopy(x, x.length - d, y, 0, d);
                    System.arraycopy(x, 0, y, d, bits - d);
                // SHIFT_LOGICAL_LEFT
                } else {
                    if (d >= bits) {
                        d = bits;
                    }

                    Arrays.fill(y, 0, d, Value.FALSE);
                    System.arraycopy(x, 0, y, d, bits - d);
                }
                vy = Value.create(y);
            }
        } else {
            vy = Value.createError(dataWidth);
        }

        // propagate them
        int delay = dataWidth.getWidth() * (3 * Adder.PER_DELAY);
        state.setPort(OUT, vy, delay);
    }

    @Override
    public void paintInstance(InstancePainter painter) {
        Graphics g = painter.getGraphics();
        painter.drawBounds();

        painter.drawPorts();

        Location loc = painter.getLocation();
        int x = loc.getX() - 15;
        int y = loc.getY();
        Object shift = painter.getAttributeValue(ATTR_SHIFT);
        g.setColor(Color.BLACK);
        if (shift == SHIFT_LOGICAL_RIGHT) {
            g.fillRect(x, y - 1, 8, 3);
            drawArrow(g, x + 10, y, -4);
        } else if (shift == SHIFT_ARITHMETIC_RIGHT) {
            g.fillRect(x, y - 1, 2, 3);
            g.fillRect(x + 3, y - 1, 5, 3);
            drawArrow(g, x + 10, y, -4);
        } else if (shift == SHIFT_ROLL_RIGHT) {
            g.fillRect(x, y - 1, 5, 3);
            g.fillRect(x + 8, y - 7, 2, 8);
            g.fillRect(x, y - 7, 2, 8);
            g.fillRect(x, y - 7, 10, 2);
            drawArrow(g, x + 8, y, -4);
        } else if (shift == SHIFT_ROLL_LEFT) {
            g.fillRect(x + 6, y - 1, 4, 3);
            g.fillRect(x + 8, y - 7, 2, 8);
            g.fillRect(x, y - 7, 2, 8);
            g.fillRect(x, y - 7, 10, 2);
            drawArrow(g, x + 3, y, 4);
        // SHIFT_LOGICAL_LEFT
        } else {
            g.fillRect(x + 2, y - 1, 8, 3);
            drawArrow(g, x, y, 4);
        }
    }

    private void drawArrow(Graphics g, int x, int y, int d) {
        int[] px = { x + d, x, x + d };
        int[] py = { y + d, y, y - d };
        g.fillPolygon(px, py, 3);
    }
}
